U.S. patent application number 16/940562 was filed with the patent office on 2020-11-12 for cage and roller assembly.
This patent application is currently assigned to JTEKT CORPORATION. The applicant listed for this patent is JTEKT CORPORATION. Invention is credited to Shigeo KAMAMOTO, Junji MURATA, Yuki SHISHIHARA.
Application Number | 20200355223 16/940562 |
Document ID | / |
Family ID | 1000004986399 |
Filed Date | 2020-11-12 |
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United States Patent
Application |
20200355223 |
Kind Code |
A1 |
MURATA; Junji ; et
al. |
November 12, 2020 |
CAGE AND ROLLER ASSEMBLY
Abstract
A cage and roller assembly includes a plurality of rollers to be
brought into rolling contact with a raceway surface provided on the
outer periphery of a shaft, and an annular cage that retains the
rollers. Lubricating oil is supplied through an oil supply hole
that is provided inside the shaft and is open at the raceway
surface. The cage includes a pair of annular portions, and a
plurality of cage bars that couple the annular portions together
and are arranged with intervals in a circumferential direction. The
rollers are housed in pockets each formed between the pair of
annular portions and between the cage bars that are adjacent to
each other in the circumferential direction. The cage has an inner
recessed groove that is provided on a radially inner surface of the
cage bar and extends through the annular portions in an axial
direction.
Inventors: |
MURATA; Junji; (Kashiba-shi,
JP) ; KAMAMOTO; Shigeo; (Kashiwara-shi, JP) ;
SHISHIHARA; Yuki; (Kashiwara-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
JTEKT CORPORATION |
Osaka-shi |
|
JP |
|
|
Assignee: |
JTEKT CORPORATION
Osaka-shi
JP
|
Family ID: |
1000004986399 |
Appl. No.: |
16/940562 |
Filed: |
July 28, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16359437 |
Mar 20, 2019 |
10767701 |
|
|
16940562 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16C 2361/61 20130101;
F16C 33/4623 20130101; F16C 19/26 20130101; F16C 33/6651
20130101 |
International
Class: |
F16C 33/66 20060101
F16C033/66; F16C 19/26 20060101 F16C019/26; F16C 33/46 20060101
F16C033/46 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 27, 2018 |
JP |
2018-059735 |
Claims
1. A planetary gearing mechanism, comprising: a planetary gear, and
a support structure that supports the planetary gear, wherein: the
support structure comprises (i) a carrier and (ii) a cage and
roller assembly; the carrier comprises a disc-shaped body, a shaft,
and a retaining member; a first side washer is provided between (i)
the disc-shaped body and (ii) the cage and roller assembly and the
planetary gear; a second side washer is provided between (i) the
retaining member and (ii) the cage and roller assembly and the
planetary gear; the cage and roller assembly comprises: a plurality
of rollers configured to roll along a raceway surface provided on
an outer periphery of the shaft; and an annular cage that retains
the rollers; the first and second side washers are located axially
adjacent to the cage, an oil supply hole is provided inside the
shaft and is open at the raceway surface, the cage includes: a pair
of annular portions; and a plurality of cage bars that couple the
pair of annular portions together and are arranged at intervals in
a circumferential direction, the rollers are housed in pockets each
formed between the pair of annular portions and between the cage
bars that are adjacent to each other in the circumferential
direction, and the cage has inner recessed grooves, each inner
recessed groove being provided on a radially inner surface of a
respective one of the cage bars and extending through the annular
portions in an axial direction.
2. The planetary gearing mechanism according to claim 1, wherein
the cage further includes: an annular recess provided on an axially
outer side and a radially inner side of one of the annular
portions, the inner recessed grooves being open at the annular
recess; and an annular protrusion that is provided on a radially
outer side of the annular recess and includes a face adjacent to
one of the first and second side washers located axially adjacent
to the cage.
3. The planetary gearing mechanism according to claim 2, wherein a
diameter of an inner peripheral surface of the annular protrusion
is larger than a diameter of an imaginary circumscribed circle
passing through groove bottoms of a plurality of the inner recessed
grooves, and a face of the annular recess where the inner recessed
grooves are open has a flat surface portion on a radially outer
side of open ends of the inner recessed grooves.
4. The planetary gearing mechanism according to claim 2, wherein a
radial dimension of the face of the annular protrusion is 50% or
more of a radial dimension of one of the annular portions.
5. The planetary gearing mechanism according to claim 1, wherein a
difference between a radius of an imaginary inscribed circle
passing through the radially inner surfaces of the plurality of
cage bars and a radius of the shaft is 0.5 millimeters or
smaller.
6. The planetary gearing mechanism according to claim 1, wherein
the cage is guided by the planetary gear located on a radially
outer side of the cage.
7. The planetary gearing mechanism according to claim 1, wherein
each of the cage bars has one of the inner recessed grooves.
Description
INCORPORATION BY REFERENCE
[0001] The disclosure of Japanese Patent Application No.
2018-059735 filed on Mar. 27, 2018 including the specification,
drawings and abstract, is incorporated herein by reference in its
entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to a cage and roller assembly
including a plurality of rollers and an annular cage that retains
the rollers.
2. Description of the Related Art
[0003] There is known a transmission including a planetary gearing
mechanism in, for example, automobiles. FIG. 9 is a sectional view
illustrating a planetary gear 90 provided in the planetary gearing
mechanism, and a support structure 100 for the planetary gear 90.
The support structure 100 includes a carrier (support member) 91
and a cage and roller assembly 92. The carrier 91 includes a
disc-shaped body 93, a shaft 94, and a retaining member 95. A base
94a of the shaft 94 is fixed to the body 93. The retaining member
95 is attached to a tip 94b of the shaft 94. The annular planetary
gear 90 is provided between the body 93 and the retaining member
95. The planetary gear 90 rotates about the shaft 94. In order to
smooth the rotation, the cage and roller assembly 92 is provided
between the planetary gear 90 and the shaft 94 (see, for example,
Japanese Patent Application Publication No. 2009-8139 (JP 2009-8139
A)).
[0004] The cage and roller assembly 92 includes a plurality of
rollers 96 and an annular cage 97. The rollers 96 are brought into
rolling contact with a raceway surface 94c provided on the outer
periphery of the shaft 94. The cage 97 retains the rollers 96. A
side washer 98 is provided between the body 93 and each of the cage
and roller assembly 92 and the planetary gear 90. Another side
washer 98 is provided between the retaining member 95 and each of
the cage and roller assembly 92 and the planetary gear 90. A small
clearance is provided between the side washer 98 and each of the
cage 97 and the planetary gear 90.
[0005] When the planetary gear 90 rotates, the cage and roller
assembly 92 rotates about the shaft 94. If the roller 96 is, for
example, skewed during the rotation, the cage 97 moves in an axial
direction, and is brought into contact with the side washer 98.
Particularly when the planetary gear 90 rotates at high speed, a
problem arises in that the temperature of the contact portion
between the cage 97 and the side washer 98 increases to cause
seizure or a frictional resistance increases.
SUMMARY OF THE INVENTION
[0006] It is one object of the present invention to provide a cage
and roller assembly in which a temperature increase can be
suppressed and a frictional resistance can be reduced even if a
cage is brought into contact with a mating member (side washer or
the like) located axially adjacent to the cage.
[0007] A cage and roller assembly according to one aspect of the
present invention has the following features in its structure. That
is, the cage and roller assembly includes a plurality of rollers
and an annular cage. The rollers are brought into rolling contact
with a raceway surface provided on an outer periphery of a shaft.
The cage retains the rollers. The cage and roller assembly is
supplied with lubricating oil through an oil supply hole that is
provided inside the shaft and is open at the raceway surface. The
cage includes a pair of annular portions, and a plurality of cage
bars that couple the pair of annular portions together and are
arranged with intervals in a circumferential direction. The rollers
are housed in pockets each formed between the pair of annular
portions and between the cage bars that are adjacent to each other
in the circumferential direction. The cage has an inner recessed
groove that is provided on a radially inner surface of the cage bar
and extends through the annular portions in an axial direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The foregoing and further features and advantages of the
invention will become apparent from the following description of
example embodiments with reference to the accompanying drawings,
wherein like numerals are used to represent like elements and
wherein:
[0009] FIG. 1 is a sectional view illustrating a planetary gear and
a support structure for the planetary gear;
[0010] FIG. 2 is a perspective view of a cage and roller
assembly;
[0011] FIG. 3 is a sectional view illustrating a part of a
cage;
[0012] FIG. 4 is a sectional view of cage bars at their cage bar
bodies;
[0013] FIG. 5 is a sectional view of the cage bars at their
detachment preventing portions;
[0014] FIG. 6 is an illustration of the cage that is viewed from an
axially outer side;
[0015] FIG. 7 is a sectional view of cage bars (other form) at
their cage bar bodies;
[0016] FIG. 8 is a sectional view illustrating an axial center
portion of the cage bar and rollers; and
[0017] FIG. 9 is a sectional view illustrating a planetary gear and
a support structure for the planetary gear according to related
art.
DETAILED DESCRIPTION OF EMBODIMENTS
[0018] A cage and roller assembly of the present invention is
applied to various rotary devices. A cage and roller assembly 20 in
the form described herein is included in a support structure 9 that
supports a planetary gear 10 provided in a planetary gearing
mechanism. FIG. 1 is a sectional view illustrating the planetary
gear 10 and the support structure 9 for the planetary gear 10.
[0019] The support structure 9 includes a carrier (support member)
11 and the cage and roller assembly 20. The carrier 11 includes a
disc-shaped body 12, a shaft 13, and a retaining member 14. The
shaft 13 has a circular shape in cross section. A base 13a of the
shaft 13 is fixed to the body 12. The retaining member 14 is
attached to a tip 13b of the shaft 13. The annular planetary gear
10 is provided between the body 12 and the retaining member 14. The
planetary gear 10 rotates about the shaft 13. In order to smooth
the rotation, the cage and roller assembly 20 is provided between
the planetary gear 10 and the shaft 13. A central axis of the cage
and roller assembly 20 coincides with a central axis of the shaft
13. The shaft 13 is a linear member having a fixed shape in cross
section along an axial direction. In this embodiment, the "axial
direction" is a direction along a central axis C0 of the cage and
roller assembly 20 (shaft 13). Any direction parallel to the
central axis C0 is also referred to as the axial direction.
[0020] The cage and roller assembly 20 includes a plurality of
rollers 21 and an annular cage 22. The cage 22 retains the rollers
21. The axial dimensions of the planetary gear 10 and the cage 22
are substantially equal to each other. A side washer 15 is provided
between the body 12 and each of the cage and roller assembly 20 and
the planetary gear 10. Another side washer 15 is provided between
the retaining member 14 and each of the cage and roller assembly 20
and the planetary gear 10. The side washer 15 is a mating member
where a face 27 of the cage 22 may be brought into contact.
[0021] The shaft 13 is provided with a first hole 16 and a second
hole 17. The first hole 16 extends in the axial direction. The
second hole 17 extends in a radial direction from a part of the
first hole 16. The second hole 17 is open at the outer peripheral
surface of the shaft 13. The outer peripheral surface of the shaft
13 includes a raceway surface 18. The rollers 21 are brought into
rolling contact with the raceway surface 18. The raceway surface 18
is hereinafter referred to as "inner raceway surface 18". The inner
peripheral surface of the planetary gear 10 serves as a raceway
surface 19. The rollers 21 are brought into rolling contact with
the raceway surface 19. The raceway surface 19 is hereinafter
referred to as "outer raceway surface 19". Although illustration is
omitted, a tubular member (bush) may be provided on the inner
periphery of the planetary gear 10. In this case, the inner
peripheral surface of the tubular member serves as the outer
raceway surface 19. The first hole 16 is supplied with lubricating
oil. The lubricating oil flows through the second hole 17, and is
supplied to the cage and roller assembly 20 through an opening 18a
on the inner raceway surface 18 of the shaft 13. The lubricating
oil is used for lubricating the cage and roller assembly 20. That
is, the cage and roller assembly 20 is supplied with the
lubricating oil through oil supply holes (first hole 16 and second
hole 17) that are provided inside the shaft 13 and are open at the
inner raceway surface 18. The second hole 17 (opening 18a) is open
at an axial center region of the inner raceway surface 18. The
axial center region is located at the same position in the axial
direction as that of an axial center portion of the cage and roller
assembly 20.
[0022] As described above, the cage and roller assembly 20 includes
the rollers 21 and the cage 22. The cage and roller assembly 20 of
this embodiment does not include an inner ring and an outer ring
that are provided in a general rolling bearing (for example, a
cylindrical roller bearing). When the cage and roller assembly 20
rotates, the rollers 21 are brought into rolling contact with the
inner raceway surface 18 provided on the outer periphery of the
shaft 13 and the outer raceway surface 19 provided on the inner
periphery of the planetary gear 10. Although illustration is
omitted, the cage and roller assembly of the present invention may
have a structure including the outer ring.
[0023] FIG. 2 is a perspective view of the cage and roller assembly
20 illustrated in FIG. 1. The roller 21 is a needle roller having a
shape of an elongated column. The cage 22 includes a pair of
annular portions 23 and 23 and a plurality of cage bars 24. The
annular portions 23 and 23 are provided away from each other in the
axial direction. The cage bars 24 are arranged with intervals in a
circumferential direction, and couple the annular portions 23 and
23 together. Pockets 25 are each provided between the annular
portions 23 and 23 and between circumferentially adjacent cage bars
24 and 24. One roller 21 is housed in each pocket 25. The roller 21
is formed of steel (for example, bearing steel). The cage 22 is
formed of a resin (for example, a polyphenylene sulfide resin:
PPS).
[0024] The annular portion 23 on one side in the axial direction
and the annular portion 23 on the other side in the axial direction
are symmetrical on the right and left (one side and the other side
in the axial direction) but have the same shape. All the cage bars
24 have the same shape as well. In each annular portion 23, a side
closer to the pocket 25 in the axial direction is referred to as
"axially inner side", and a side opposite to the pocket 25 in the
axial direction is referred to as "axially outer side". FIG. 3 is a
sectional view illustrating a part of the cage 22 (right part in
FIG. 2). An annular recess 26 is formed on the axially outer side
of the annular portion 23 (right side in FIG. 3). The annular
recess 26 is formed on a radially inner side of the annular portion
23. Therefore, the annular portion 23 has an annular protrusion 28
on its radially outer side. The annular recess 26 and the annular
protrusion 28 are formed continuously over the entire
circumference. The face 27 (first face 27) of the annular
protrusion 28 on the axially outer side is a contact surface that
may be brought into contact with the side washer 15. A face 29
(second face 29) of the annular recess 26 on the axially outer side
is kept out of contact with the side washer 15. Both the first face
27 and the second face 29 are ring-shaped surfaces. A cylindrical
surface is provided between the first face 27 and the second face
29. The cylindrical surface is an inner peripheral surface 30 of
the annular protrusion 28.
[0025] A clearance is provided between the pocket 25 (see FIG. 2)
provided in the cage 22 and the roller 21. Therefore, the cage 22
and the roller 21 can slightly be displaced relative to each other
in the radial direction. When the cage 22 is displaced in the
radial direction in a state in which the cage and roller assembly
20 is attached between the shaft 13 and the planetary gear 10, an
outer peripheral surface 31 of each annular portion 23 is brought
into contact with an inner peripheral surface 32 (outer raceway
surface 19) of the planetary gear 10 (see FIG. 3). An inner
peripheral surface 33 of the annular portion 23 cannot be brought
into contact with an outer peripheral surface 34 (inner raceway
surface 18) of the shaft 13. In order to achieve this structure, a
radial clearance e1 formed between the inner peripheral surface 32
of the planetary gear 10 and the outer peripheral surface 31 of the
annular portion 23 is set smaller than a radial clearance e2 formed
between the inner peripheral surface 33 of the annular portion 23
and the outer peripheral surface 34 of the shaft 13 (e1<e2) in a
state in which the planetary gear 10 and the cage 22 are arranged
concentrically. The clearance e2 is 0.5 millimeters or smaller, and
the clearance e1 is smaller than the clearance e2 (0.5
millimeters.gtoreq.e2>e1). With this structure, the outer
peripheral surface 31 of the annular portion 23 is brought into
sliding contact with the inner peripheral surface 32 of the
planetary gear 10 when the cage and roller assembly 20 rotates.
Therefore, the cage 22 can stably rotate along the inner peripheral
surface 32 by being guided by the planetary gear 10. That is, the
guiding method for the cage 22 of this embodiment is a method in
which the cage 22 is guided by a member (planetary gear 10) located
on a radially outer side of the cage 22. The cage 22 is guided by
the outer peripheral surface 31 of the annular portion 23, and
therefore the outer peripheral surface 31 is referred to as "guide
surface 31" in the following description.
[0026] For example, when an operation of attaching the cage and
roller assembly 20 to an inner peripheral side of the planetary
gear 10 is performed and when the cage and roller assembly 20 is
transported alone, it is necessary that the roller 21 housed in the
pocket 25 (see FIG. 2) be prevented from detaching radially outward
or radially inward from the pocket 25. In view of this, each cage
bar 24 of the cage 22 has detachment preventing portions 41 that
prevent the roller 21 from detaching from the pocket 25. The
detachment preventing portions 41 are provided on both sides of the
cage bar 24 in the axial direction. Each cage bar 24 has a cage bar
body 42 between the detachment preventing portions 41 and 41 on
both sides in the axial direction. The cage bar body 42 has an oil
reservoir bottom face 43 on its radially outer side. The function
of the oil reservoir bottom face 43 is described later. In FIG. 2,
the axial length of the cage bar body 42 is J1, and the axial
length of the detachment preventing portion 41 is J2. The cage bar
body 42 is longer in the axial direction than the sum of the axial
lengths of the detachment preventing portions 41 located on both
sides in the axial direction (J1>2.times.J2). The detachment of
the roller 21 is prevented such that a part of the detachment
preventing portion 41 is brought into contact with the end of the
roller 21 from the radially outer side or the radially inner
side.
[0027] As described above, an axial center portion of the cage bar
24 that is located between the two ends (detachment preventing
portions 41 and 41) is the cage bar body 42. A large clearance G1
(see FIG. 4) is formed between the cage bar body 42 and the roller
21. A clearance G2 (see FIG. 5) smaller than the clearance G1 is
formed between the detachment preventing portion 41 and the roller
21. Therefore, when the roller 21 and the cage 22 move relative to
each other, the roller 21 is brought into contact with the
detachment preventing portions 41 and 41, but is kept out of
contact with the cage bar body 42. FIG. 4 is a sectional view of
the cage bars 24 at their cage bar bodies 42. FIG. 5 is a sectional
view of the cage bars 24 at their detachment preventing portions
41.
[0028] As illustrated in FIG. 2 and FIG. 5, each detachment
preventing portion 41 has outer claws 40a on its radially outer
portion 41a. The outer claw 40a protrudes radially outward with
respect to the cage bar body 42, and also protrudes in the
circumferential direction. Since the outer claw 40a protrudes in
the circumferential direction, the radially outer portion 41a has a
shape that expands in the circumferential direction as compared to
the cage bar body 42. The detachment preventing portion 41 also has
inner claws 40b on its radially inner portion 41b. The inner claw
40b protrudes in the circumferential direction. Since the inner
claw 40b protrudes in the circumferential direction, the radially
inner portion 41b has a shape that expands in the circumferential
direction as compared to the cage bar body 42. A distance B1
between the outer claw 40a on one side in the circumferential
direction and the outer claw 40a on the other side in the
circumferential direction across the pocket 25 is smaller than a
diameter D of the roller 21 (B1<D). A distance B2 between the
inner claw 40b on one side in the circumferential direction and the
inner claw 40b on the other side in the circumferential direction
across the pocket 25 is smaller than the diameter D of the roller
21 (B2<D). The roller 21 is interposed, with a distance, between
the outer claw 40a and the inner claw 40b located on the radially
inner side of the outer claw 40a. Therefore, the roller 21 does not
detach radially outward or radially inward from the pocket 25. In
order to house the roller 21 in the pocket 25, the roller 21 is
moved closer to the pocket 25 from the radially outer side, and is
pressed to elastically deform the outer claw 40a. As illustrated in
FIG. 2, a recess 47 is provided between the outer claw 40a and the
annular portion 23, and the outer claw 40a is not continuous with
the annular portion 23 (not connected to the annular portion 23).
This structure facilitates the elastic deformation of the outer
claw 40a.
[0029] The radially outer portion 41a including the outer claws 40a
protrudes radially outward with respect to the oil reservoir bottom
face 43 of the cage bar body 42. The protruding region falls within
the range of the detachment preventing portion 41, and the axial
length of the protruding region is J2. In this embodiment, the
radially outer portion 41a including the outer claws 40a and the
radially inner portion 41b including the inner claws 40b have the
same axial length.
[0030] As illustrated in FIG. 4, the sectional shape of each cage
bar body 42 (sectional shape in cross section orthogonal to the
axial direction) is a trapezoidal shape having a long side located
on its radially outer side. The radially outer surface of the cage
bar body 42 serves as the oil reservoir bottom face 43 located on
the radially inner side with respect to the guide surface 31 (see
FIG. 2). The function of the oil reservoir bottom face 43 is
described later. As illustrated in FIG. 3, a space K is formed
between the oil reservoir bottom face 43 and the outer raceway
surface 19 of the planetary gear 10. The lubricating oil can be
stored in the space K.
[0031] FIG. 4 and FIG. 5 illustrate a state in which a central axis
of a pitch diameter of a set of the rollers 21 coincides with a
central axis of the cage 22 and the roller 21 (central axis C1 of
the roller 21) is located at a middle point in the circumferential
direction between a pair of circumferentially adjacent cage bars 24
(in the pocket 25). This state is referred to as "reference state".
When the cage 22 and the roller 21 in the reference state move
relative to each other in the circumferential direction, the roller
21 is brought into contact with a part of the cage bar 24. The part
of the cage bar 24 where the roller 21 is brought into contact is
the detachment preventing portion 41. Even through the relative
movement, the roller 21 is not brought into contact with the cage
bar body 42. That is, if the roller 21 is skewed or advances with a
delay in the pocket 25 of the cage 22, the roller 21 is brought
into contact with the detachment preventing portion 41 at an axial
end. The posture of the roller 21 is maintained at both axial ends.
Thus, the posture of the roller 21 is stable in the pocket 25.
[0032] The cage and roller assembly 20 of this embodiment has a
first axial guide structure. With the first axial guide structure,
the lubricating oil supplied through the opening 18a on the inner
raceway surface 18 of the shaft 13 (see FIG. 1) is guided to both
sides in the axial direction along the radially inner surface of
the cage 22 and is supplied to the faces (27, 29) on both sides in
the axial direction. The cage and roller assembly 20 of this
embodiment also has a radial guide structure. With the radial guide
structure, the lubricating oil supplied through the opening 18a
passes radially outward through a space between the cage bar 24 of
the cage 22 and the roller 21 and is supplied to the space K (see
FIG. 3) between the cage bar 24 and the planetary gear 10. The cage
and roller assembly 20 of this embodiment also has a second axial
guide structure. With the second axial guide structure, the
lubricating oil in the space K is supplied to a space between the
guide surface 31 of the annular portion 23 and the inner peripheral
surface 32 of the planetary gear 10. The guide structures are
described below.
[0033] The first axial guide structure is described below. As
illustrated in FIG. 2 and FIG. 3, an inner recessed groove 36 is
formed on a radially inner surface 35 of each cage bar 24. The
inner recessed groove 36 is provided over the total length of the
cage bar 24, and is also formed on the inner peripheral surface 33
of each annular portion 23. The radially inner surface 35 and the
inner peripheral surface 33 have shapes conforming to a common
imaginary cylindrical surface. The inner recessed groove 36
continues from the radially inner surface 35, and extends through
the inner peripheral portion of the annular portion 23 (portion
including the inner peripheral surface 33) in the axial direction.
Therefore, the inner recessed groove 36 is open at the second face
29. The position on the second face 29 where the inner recessed
groove 36 is open corresponds to an open end 37. In this
embodiment, the radially inner surface 35 of the cage bar body 42
is an imaginary surface because the inner recessed groove 36 is
formed over the substantially entire radially inner surface 35.
[0034] FIG. 6 is an illustration of the cage 22 that is viewed from
the axially outer side. In FIG. 6, the inner peripheral surface 32
of the planetary gear 10 and the outer peripheral surface 34 of the
shaft 13 are represented by long dashed double-short dashed lines.
The groove shape (sectional shape) of each inner recessed groove 36
is an arc shape. The groove shape of the inner recessed groove 36
on the second face 29 (open end 37) is also an arc shape. The long
dashed short dashed line illustrated in FIG. 6 represents an
imaginary circumscribed circle Q1 passing through groove bottoms of
the plurality of inner recessed grooves 36. A diameter L2 of the
inner peripheral surface 30 of the annular protrusion 28 is larger
than a diameter L1 of the imaginary circumscribed circle Q1
(L2>L1). Therefore, the second face 29 has (first) flat surface
portions 39 on both sides of the open end 37 of each inner recessed
groove 36 in the circumferential direction, and a (second) flat
surface portion 38 on a radially outer side of the open end 37. The
diameter L1 and the diameter L2 are values on the second face 29.
The groove shape of the inner recessed groove 36 may be a shape
other than the arc shape.
[0035] A radial dimension T1 of the first face 27 of the annular
protrusion 28 is 50% or more of a radial dimension T0 of the
annular portion 23. The upper limit of the radial dimension T1 is
75% of the radial dimension T0. That is, the radial dimension T1 is
50% or more and 75% or less of the radial dimension T0. The radial
dimension T1 of the first face 27 corresponds to a difference
between the radius of the outer peripheral surface (guide surface)
31 of the annular portion 23 and the radius of the inner peripheral
surface 30 of the annular protrusion 28. The radial dimension T0 of
the annular portion 23 corresponds to a difference between the
radius of the outer peripheral surface (guide surface) 31 and the
radius of the inner peripheral surface 33.
[0036] A specific example of the size of the cage and roller
assembly 20 is described. In this embodiment, an outside diameter
L3 of the cage 22 (outside diameter of the annular portion 23) is
10 millimeters. The radial dimension T1 of the first face 27 of the
annular protrusion 28 is 1 millimeter. The size of the cage 22
(outside diameter L3) may be changed to any value. Even if the size
of the cage 22 is changed, the radial dimension T1 of the first
face 27 is preferably 1 millimeter or larger. That is, L3-L2 is
preferably 2 millimeters or larger (L3-L2.gtoreq.2
millimeters).
[0037] As described above (see FIG. 3), the radially inner surface
35 of the cage bar 24 and the inner peripheral surface 33 of the
annular portion 23 have shapes conforming to the common imaginary
cylindrical surface. A difference (r1-r2) between a radius r1 of an
imaginary inscribed circle passing through the radially inner
surfaces 35 of the cage bars 24 and a radius r2 of the shaft 13 is
a value equal to that of the clearance e2. The difference (r1-r2)
between the radius r1 of the imaginary inscribed circle and the
radius r2 of the shaft 13 is 0.5 millimeters or smaller. That is,
the clearance e2 formed between the radially inner surface 35 of
the cage bar 24 and the shaft 13 is larger than the clearance e1 on
the planetary gear 10 side (see FIG. 3 and FIG. 6), but is 0.5
millimeters or smaller (e2.ltoreq.0.5 millimeters). Thus, the
clearance e2 is small.
[0038] As described above, the cage 22 (see FIG. 2 and FIG. 3)
provided in the cage and roller assembly 20 of this embodiment has
the inner recessed grooves 36. The inner recessed groove 36 is
provided on the radially inner surface 35 of each cage bar 24, and
extends through each annular portion 23 (its inner peripheral
portion) in the axial direction. According to the cage and roller
assembly 20, the lubricating oil supplied through the oil supply
holes 16 and 17 that are open at the inner raceway surface 18 of
the shaft 13 (see FIG. 1) is guided in the axial direction through
the inner recessed grooves 36 to reach the faces 27 and 29 of the
annular portions 23. Therefore, even if the cage 22 is brought into
contact with the side washer 15 located axially adjacent to the
cage 22, a temperature increase can be suppressed and a frictional
resistance can be reduced by the lubricating oil that reaches the
face 27 of the annular portion 23.
[0039] The cage 22 has the annular recesses 26 and the annular
protrusions 28 at the axial ends. The annular recess 26 is provided
on the axially outer side and the radially inner side of the
annular portion 23, and the inner recessed groove 36 is open at the
annular recess 26. The annular protrusion 28 is provided on the
radially outer side of the annular recess 26, and has the first
face 27 that may be brought into contact with the side washer 15
located axially adjacent to the cage 22. With this structure, the
lubricating oil guided in the axial direction through the inner
recessed groove 36 enters the annular recess 26, and is stored in
the annular recess 26. The lubricating oil in the annular recess 26
can gradually enter a space between the first face 27 and the side
washer 15, and is used for lubrication. Since the lubricating oil
is stored in the annular recess 26, the lubricity between the cage
22 and the side washer 15 can be stabilized over a long period.
[0040] As illustrated in FIG. 6, the diameter L2 of the inner
peripheral surface 30 of the annular protrusion 28 is larger than
the diameter L1 of the imaginary circumscribed circle Q1 passing
through the groove bottoms of the inner recessed grooves 36
(L2>L1). Therefore, the second face 29 where the inner recessed
grooves 36 are open has the flat surface portion 38 on the radially
outer side of the open ends 37 of the inner recessed grooves 36.
The lubricating oil guided in the axial direction through each
inner recessed groove 36 to enter the annular recess 26 is likely
to flow radially outward by a centrifugal force. The lubricating
oil flows radially outward along the flat surface portion 38 as
indicated by an arrow F1 in FIG. 6, and impinges on the inner
peripheral surface 30 of the annular protrusion 28 to flow while
the direction is changed to the circumferential direction (arrows
F2 in FIG. 6). Thus, in the cage 22 of this embodiment, the
lubricating oil is easily stored in the annular recess 26.
[0041] In order to store the lubricating oil in the annular recess
26, it is only necessary that the inner recessed grooves 36 be open
at the second face 29. Although illustration is omitted, the
diameter L1 and the diameter L2 may be equal to each other (L1=L2).
However, L2>L1 is preferable as in this embodiment. If the
diameter L1 and the diameter L2 are equal to each other (L1=L2),
the first flat surface portions 39 are formed on the second face 29
on both sides of each open end 37 in the circumferential direction.
However, the flat surface portion 38 is not formed on the radially
outer side of the open end 37. If the flat surface portion 38 is
not formed on the radially outer side of the open end 37, a part of
the lubricating oil supplied through the inner recessed groove 36
is likely to flow directly toward the first face 27 via the inner
peripheral surface 30 of the annular protrusion 28 before the
lubricating oil is stored in the annular recess 26. Thus, L2>L1
(L2.noteq.L1) is preferable in order that the lubricating oil that
reaches the annular recess 26 through the inner recessed groove 36
is caused to flow (spread: arrows F2) in the circumferential
direction to enhance the function of storing the lubricating oil in
the annular recess 26.
[0042] In this embodiment, the radial dimension T1 of the first
face 27 of the annular protrusion 28 is 50% or more of the radial
dimension T0 of the annular portion 23. According to this
structure, the first face 27 that may be brought into contact with
the side washer 15 (see FIG. 3) is not narrow. That is, the contact
area between the annular portion 23 and the side washer 15 is
secured in the annular portion 23. Particularly in this embodiment,
a problem arises in terms of wear of the cage 22 due to the contact
between the cage 22 and the side washer 15 if the cage 22 is formed
of a resin and the side washer 15 is formed of a metal. The
structure described above suppresses the wear of the cage 22
(annular portion 23).
[0043] In this embodiment (see FIG. 3 and FIG. 6), the difference
(r1-r2) between the radius r1 of the imaginary inscribed circle
passing through the radially inner surfaces 35 of the cage bars 24
and the radius r2 of the shaft 13 is 0.5 millimeters or smaller.
According to this structure, the clearance e2 formed between the
radially inner surface 35 of the cage bar 24 and the shaft 13 is
small. Therefore, the lubricating oil passing through the inner
recessed groove 36 is covered with the outer peripheral surface 34
of the shaft 13 from the radially inner side. The space formed
between the inner recessed groove 36 and the outer peripheral
surface 34 of the shaft 13 serves as a passage of the lubricating
oil. Through the passage, the lubricating oil is guided in the
axial direction. Thus, the lubricating oil reaches the faces 27 and
29 of the annular portions 23 more easily.
[0044] As described above, in the first axial guide structure
including the inner recessed grooves 36, the lubricating oil
supplied through the opening 18a on the inner raceway surface 18
(see FIG. 1) can be guided to both sides in the axial direction
along the radially inner surface of the cage 22 and supplied to the
faces (27, 29) on both sides in the axial direction. Therefore, a
sliding resistance between the cage 22 and the side washer 15 can
be reduced, and heat generation can be suppressed. Thus, the cage
and roller assembly 20 can have high rotation performance. In this
embodiment, the cage and roller assembly 20 having the structure
described above is used in the support structure 9 that supports
the planetary gear 10 (see FIG. 1). Thus, the temperature increase
can be suppressed in the cage and roller assembly 20. Further, the
torque of the planetary gearing mechanism can be reduced because
the frictional resistance is reduced.
[0045] The radial guide structure is described below. FIG. 4 is a
sectional view of the cage bars 24 at their cage bar bodies 42.
FIG. 5 is a sectional view of the cage bars 24 at their detachment
preventing portions 41. In FIG. 4, the first clearance G1 is formed
between the cage bar body 42 and the roller 21 located
circumferentially adjacent to the cage bar body 42 in the reference
state. In FIG. 5, the second clearance G2 is formed between the
detachment preventing portion 41 and the roller 21 located
circumferentially adjacent to the detachment preventing portion 41
in the reference state.
[0046] In FIG. 4 and FIG. 5, the long dashed short dashed line
represents an imaginary plane Q2 passing through the central axis
of the cage 22 and the central axis C1 of the roller 21. In FIG. 4,
the long dashed double-short dashed line represents an imaginary
reference plane Q3 parallel to the imaginary plane Q2. In the form
illustrated in FIG. 4, a face 44 of the cage bar body 42 is
provided along the imaginary reference plane Q3. The minimum value
of the clearance G1 is a minimum distance g1 from the imaginary
reference plane Q3 to the roller 21. As illustrated in FIG. 5, the
detachment preventing portion 41 has a second face 55 located on
the roller 21 side with respect to the face (first face) 44 of the
cage bar body 42. Therefore, the clearance G2 is smaller than the
clearance G1. More specifically, assuming that the minimum value
(minimum distance) of the clearance G2 formed between the
detachment preventing portion 41 and the roller 21 is g2, the
minimum value g2 is smaller than the minimum value (g1) of the
clearance G1 (g2<g1). That is, the clearance (minimum value)
formed between the cage bar 24 and the roller 21 located
circumferentially adjacent to the cage bar 24 is larger in the cage
bar body 42 at the axial center portion of the cage bar 24 than in
the detachment preventing portions 41 provided at both axial ends
of the cage bar 24. The minimum distance g1 is preferably set to
0.3 millimeters or larger. The maximum value of the minimum
distance g1 is 1 millimeter.
[0047] In FIG. 4, "A1" represents a distance between a radially
outer end 46 of the cage bar body 42 provided in one cage bar 24
and a radially outer end 46 of the cage bar body 42 provided in the
other cage bar 24 out of the pair of circumferentially adjacent
cage bars 24 and 24. "A2" represents a distance between a radially
inner end 45 of the cage bar body 42 provided in the one cage bar
24 and a radially inner end 45 of the cage bar body 42 provided in
the other cage bar 24 out of the pair of cage bars 24 and 24. In
the form illustrated in FIG. 4, the faces 44 of the cage bar bodies
42 on both sides are provided along two imaginary reference planes
Q3 parallel to the imaginary plane Q2. The distance A1 and the
distance A2 are equal to each other (A1=A2). The distance A1 is a
circumferential width of the pocket 25 on the radially outer side.
The distance A2 is a circumferential width of the pocket 25 on the
radially inner side.
[0048] Instead of the structure in which the distance A1 and the
distance A2 are equal to each other, the distance A2 may be larger
than the distance A1 (A2>A1). That is, in the cage bar bodies 42
having large clearances G1 in the pair of circumferentially
adjacent cage bars 24 and 24, it is only necessary that the
distance A2 between the radially inner ends 45 and 45 be equal to
or larger than the distance A1 between the radially outer ends 46
and 46 (A2.gtoreq.A1).
[0049] Thus, in the cage and roller assembly 20 of this embodiment,
the distance between the cage bar bodies 42 and 42 is increased on
the radially inner side. That is, it is only necessary that the
minimum value of the distance A2 be the distance A1. In order to
increase the distance between the cage bar bodies 42 and 42 on the
radially inner side, that is, to increase the distance A2, the
faces 44 of the cage bar bodies 42 may be inclined with respect to
the imaginary reference planes Q3 as illustrated in FIG. 7. The
inclination angle of the face 44 with respect to the imaginary
reference plane Q3 is .theta. (.theta.>0). In this case, the
distance A2 on the radially inner side is larger than the distance
A1 on the radially outer side (A2>A1). Thus, in the cage bar
bodies 42 in the form illustrated in FIG. 7, the faces 44 that face
the outer peripheral surface of the roller 21 are inclined with
respect to the imaginary reference planes Q3. In each cage bar 24
in the forms illustrated in FIG. 4 and FIG. 7, an intersection line
obtained through intersection of extension planes of the faces 44
on both sides in the circumferential direction is located on the
radially outer side with respect to the central axis of the cage
22.
[0050] FIG. 8 is a sectional view illustrating the axial center
portion of the cage bar 24 (that is, the cage bar body 42) and the
rollers 21. As described above, the inner recessed groove 36 is
formed on the radially inner surface 35 of the cage bar body 42.
The inner recessed groove 36 has a groove bottom face 48 and groove
side faces 49. The groove bottom face 48 is a face on a deep side
(radially outer side) of the inner recessed groove 36. The groove
side face 49 is a face extending radially inward from the groove
bottom face 48. In the case of this embodiment, the groove shape of
the inner recessed groove 36 is the arc shape, and the groove
bottom face 48 smoothly continues with the groove side faces 49 and
49 on both sides of the groove bottom face 48. In the cage bar body
42, the groove width of the inner recessed groove 36 is
(substantially) equal to the circumferential width dimension of the
radially inner surface 35. The groove width of the inner recessed
groove 36 is a maximum distance between the groove side faces 49
and 49. An acute apex 50 is interposed between one groove side face
49 and one face 44 of the cage bar body 42. An acute apex 50 is
also interposed between the other groove side face 49 and the other
face 44 of the cage bar body 42. The face 44 and the groove side
face 49 intersect each other at an acute angle. The intersecting
portion (apex 50) may be chamfered or rounded. In this case, the
extension plane of the face 44 and an extension plane of the groove
side face 49 intersect each other at an acute angle. Thus, in the
cage bar body 42, the face 44 that faces the outer peripheral
surface of the roller 21 and the groove side face 49 of the inner
recessed groove 36 continue with each other via the acute apex
50.
[0051] As described above, in the cage and roller assembly 20 of
this embodiment (see FIG. 4 and FIG. 5), the clearance (minimum
value) formed between the cage bar 24 and the roller 21 housed in
the pocket 25 is larger in the axial center portion (cage bar body
42; see FIG. 4) between the axial ends (detachment preventing
portions 41; see FIG. 5) than at the axial ends (G1>G2).
[0052] When the cage and roller assembly 20 rotates, the guide
surface 31 of the annular portion 23 provided in the cage 22 may be
brought into contact with the inner peripheral surface 32 of the
planetary gear 10. Therefore, it is necessary to supply the
lubricating oil to the space between the guide surface 31 and the
inner peripheral surface 32 of the planetary gear 10. In this
embodiment (see FIG. 1), the lubricating oil is supplied to the
cage and roller assembly 20 from the shaft 13 side on its inner
periphery. In the cage and roller assembly 20 of this embodiment,
the lubricating oil supplied through the oil supply hole (second
hole 17) that is open at the axial center region of the inner
raceway surface 18 of the shaft 13 can flow radially outward
through the space between the cage bar 24 and the roller 21. As
described above, the clearance formed between the cage bar 24 and
the roller 21 is large in the axial center portion. Therefore, the
lubricating oil supplied through the oil supply hole (second hole
17) easily reaches an outer peripheral side of the cage 22.
[0053] More specifically, in this embodiment (see FIG. 2), each
cage bar 24 has the detachment preventing portions 41 on both sides
in the axial direction. The detachment preventing portion 41 has
the outer claw 40a and the inner claw 40b between which the end of
the roller 21 is interposed with a distance on the radially outer
side and the radially inner side. The lubricating oil hardly flows
in the radial direction through a space between the detachment
preventing portion 41 and the roller 21 due to the outer claw 40a
and the inner claw 40b. In this embodiment, the clearance formed
between the roller 21 and the cage bar body 42 excluding the
detachment preventing portion 41 (see FIG. 4) is larger than the
clearance formed between the roller 21 and the detachment
preventing portion 41 (see FIG. 5) as described above (G1>G2).
Therefore, the lubricating oil supplied through the oil supply hole
(second hole 17) that is open at the axial center region of the
shaft 13 (see FIG. 1) easily reaches the outer peripheral side of
the cage 22.
[0054] As described above, even when the lubricating oil is
supplied to the inner peripheral side of the cage and roller
assembly 20, the lubricating oil easily reaches the outer
peripheral side of the cage 22 (space K; see FIG. 3) by passing
through the cage 22 in the radial direction. Then, the lubricating
oil is supplied to the space between the guide surface 31 and the
inner peripheral surface 32 of the planetary gear 10. Thus, the
cage and roller assembly 20 can have high rotation performance.
[0055] The cage bar body 42 is longer in the axial direction than
the sum of the axial lengths (J2; see FIG. 2) of the detachment
preventing portions 41 located on both sides in the axial direction
(J1>2.times.J2). Therefore, the range in which the clearance
from the roller 21 is large is wide in the axial direction. Thus,
the lubricating oil supplied through the oil supply hole (second
hole 17) easily reaches the outer peripheral side of the cage
22.
[0056] In this embodiment, each detachment preventing portion 41 is
provided with an outer recessed groove 51 as illustrated in FIG. 2
though description is given later in the second axial guide
structure. The outer recessed groove 51 serves as a passage for
causing the lubricating oil to flow toward the guide surface 31 of
the annular portion 23 from the oil reservoir bottom face 43
through the radially outer portion 41a of the detachment preventing
portion 41. With the outer recessed groove 51, the lubricating oil
stored in the space between the oil reservoir bottom face 43 and
the inner peripheral surface 32 of the planetary gear 10 (space K;
see FIG. 3) is easily supplied to the guide surface 31 through the
outer recessed groove 51.
[0057] In the axial center portions (cage bar bodies 42) having
large clearances G1 (see FIG. 4 and FIG. 7) in the pair of
circumferentially adjacent cage bars 24 and 24, the distance A2
between the radially inner ends 45 and 45 is equal to or larger
than the distance A1 between the radially outer ends 46 and 46
(A2.gtoreq.A1). According to this structure, the radially inner
opening of the pocket 25 is widened. Therefore, the lubricating oil
supplied from the shaft 13 side is easily received on the inner
peripheral side of the cage 22. As a result, the lubricating oil
reaches the outer peripheral side of the cage 22 more easily.
[0058] Particularly in the form illustrated in FIG. 7, the faces 44
are inclined with respect to the imaginary reference planes Q3 in
the axial center portions (cage bar bodies 42) having large
clearances G1. With this structure, the distance A2 is larger than
the distance A1 (A2>A1) in the axial center portions (cage bar
bodies 42) having large clearances G1 in the pair of
circumferentially adjacent cage bars 24 and 24. That is, the
radially inner opening of the pocket 25 is wider than the radially
outer opening of the pocket 25. Thus, the lubricating oil supplied
from the shaft 13 side is received on the inner peripheral side of
the cage 22 more easily.
[0059] In FIG. 7, the inclination angle of the face 44 with respect
to the imaginary reference plane Q3 is .theta.. If the inclination
angle .theta. increases, it is possible to enhance the performance
of the cage 22 that receives the lubricating oil into each pocket
25. If the inclination angle .theta. increases excessively,
however, the sectional area of each cage bar body 42 decreases, and
the strength may decrease. Although illustration is omitted, the
cage 22 is manufactured by injection molding that uses a split
mold. The split mold includes mold parts configured to move in the
radial direction (radially) in order to form the pockets 25. If the
inclination angle .theta. increases, the mold parts may be
difficult to move in the radial direction during mold removal (need
to be removed forcibly). Thus, the upper limit value of .theta. is
preferably about 5.degree. (0.ltoreq..theta.<5.degree.).
[0060] In this embodiment, the inner recessed grooves 36 are
provided on the inner peripheral side of the cage 22. As described
with reference to FIG. 8, in the cage bar body 42, the face 44 that
faces the outer peripheral surface of the roller 21 and the groove
side face 49 of the inner recessed groove 36 continue with each
other via the acute apex 50. According to this structure, if a part
of the lubricating oil flows out of the inner recessed groove 36
during the rotation of the cage and roller assembly 20, the part of
the lubricating oil can immediately flow radially outward along the
face 44 via the acute apex 50 by the centrifugal force. As a
result, the part of the lubricating oil easily reaches the outer
peripheral side of the cage 22. That is, the lubricating oil
flowing out of the inner recessed groove 36 can easily flow
radially outward along the face 44.
[0061] As described above, in the radial guide structure including
the structure in which the clearance G1 (see FIG. 4 and FIG. 7)
between the roller 21 and the axial center portion (cage bar body
42) of the cage bar 24 provided in the cage 22 is increased, the
lubricating oil supplied from the inner peripheral side of the cage
and roller assembly 20 can be supplied to the space K (see FIG. 3)
between the cage bar 24 and the inner peripheral surface 32 of the
planetary gear 10 by passing radially outward through the space
between the cage bar 24 and the roller 21. Then, the lubricating
oil is supplied to the space between the guide surface 31 and the
inner peripheral surface 32 of the planetary gear 10. Thus, a
sliding resistance can be reduced, and heat generation can be
suppressed. Accordingly, the cage and roller assembly 20 can have
high rotation performance.
[0062] The second axial guide structure is described below. As
described above (see FIG. 3), the cage 22 is provided with the oil
reservoir bottom face 43 on the radially outer side of each cage
bar body 42. The lubricating oil is stored in the space K between
the oil reservoir bottom face 43 and the inner peripheral surface
32 of the planetary gear 10. The radially outer portion 41a of each
detachment preventing portion 41 is provided between the oil
reservoir bottom face 43 and the guide surface 31 of the annular
portion 23. The radially outer portion 41a is a portion that
protrudes toward the inner peripheral surface 32 of the planetary
gear 10 with respect to the oil reservoir bottom face 43.
Therefore, the radially outer portion 41a is an obstacle to the
lubricating oil that is stored in the space K and is likely to flow
toward the guide surface 31. In view of this, the radially outer
portion 41a is provided with the outer recessed groove 51 as the
passage for causing the lubricating oil to flow toward the guide
surface 31 from the space K (see FIG. 2 and FIG. 3). The groove
shape (sectional shape) of the outer recessed groove 51 of this
embodiment is an arc shape. The groove shape of the outer recessed
groove 51 may be a shape other than the arc shape.
[0063] In the cage bar 24, the oil reservoir bottom face 43 and the
outer recessed groove 51 are continuously provided side by side in
the axial direction. The outer recessed groove 51 and the annular
portion 23 are also continuously provided side by side in the axial
direction. The oil reservoir bottom face 43 and a bottom 51a (see
FIG. 3) of the outer recessed groove 51 are located at the same
position in the radial direction. The guide surface 31 is located
on the radially outer side with respect to the bottom 51a of the
outer recessed groove 51. In the range of the outer recessed groove
51, an inclined surface 53 is provided between the bottom 51a and
the guide surface 31. That is, the inclined surface 53 is a surface
connected to the guide surface 31 from the bottom 51a of the outer
recessed groove 51. The inclined surface 53 is a surface extending
radially outward with decreasing distance from the annular portion
23.
[0064] Description is given of the radially outer portion 41a
having the outer recessed groove 51. The radially outer portion 41a
has the outer claws 40a. The outer claw 40a is located on the
radially outer side with respect to the oil reservoir bottom face
43, and protrudes in the circumferential direction to cover a part
of the roller 21 from the radially outer side. Thus, the radially
outer portion 41a including the outer claws 40a is located
relatively on the radially outer side, but its position is limited.
That is, a radially outer surface 52 of the radially outer portion
41a is located on the radially inner side with respect to the guide
surface 31. The outer recessed groove 51 is recessed from the
radially outer surface 52.
[0065] As described above, the cage and roller assembly 20 of this
embodiment has the following structure. For example, when the cage
22 and the rollers 21 are transported as a unit, it is necessary
that the rollers 21 be prevented from detaching from the pockets 25
of the cage 22. In view of this, the detachment preventing portions
41 are provided on both sides of each cage bar 24 of the cage 22 in
the axial direction. The detachment preventing portion 41 has the
outer claw 40a that covers a part of the roller 21 from the
radially outer side. In order to guide the rotation of the cage 22,
the guide surface 31 of each annular portion 23 may be brought into
contact with the inner peripheral surface 32 of the planetary gear
10. Therefore, it is necessary to supply the lubricating oil to the
space between the guide surface 31 and the inner peripheral surface
32 of the planetary gear 10. The cage bar body 42 of the cage bar
24 has the oil reservoir bottom face 43 on its radially outer side.
The oil reservoir bottom face 43 is located on the radially inner
side with respect to the guide surface 31. According to this
structure, the lubricating oil is stored in the space between the
oil reservoir bottom face 43 and the inner peripheral surface 32 of
the planetary gear 10. In the cage and roller assembly 20, the
detachment preventing portions 41 are provided on both sides of the
oil reservoir bottom face 43 in the axial direction. The detachment
preventing portion 41 may keep the lubricating oil stored on the
oil reservoir bottom face 43 from being supplied to the guide
surface 31.
[0066] As the second axial guide structure, each detachment
preventing portion 41 is provided with the outer recessed groove
51. The outer recessed groove 51 constitutes the passage for
causing the lubricating oil to flow toward the guide surface 31
from the oil reservoir bottom face 43 through the radially outer
portion 41a of the detachment preventing portion 41. Therefore, the
lubricating oil stored in the space between the oil reservoir
bottom face 43 and the inner peripheral surface 32 of the planetary
gear 10 is supplied to the guide surface 31 through the outer
recessed groove 51. As a result, the cage and roller assembly 20
can have high rotation performance.
[0067] As described above, in the cage and roller assembly 20 of
this embodiment, the lubricating oil is supplied through the oil
supply hole (second hole 17) that is open at the axial center
region of the inner raceway surface 18 provided in the shaft 13
(see FIG. 1). The lubricating oil supplied through the oil supply
hole (second hole 17) can flow radially outward through the space
between the cage bar 24 of the cage 22 and the roller 21. As
described in the radial guide structure, the clearance (minimum
value) formed between the cage bar 24 and the roller 21 housed in
the pocket 25 is larger in the cage bar body 42 at the center in
the axial direction than in the detachment preventing portions 41
on both sides in the axial direction. Therefore, the lubricating
oil supplied through the oil supply hole (second hole 17) easily
reaches the outer peripheral side of the cage 22 through the space
between the cage bar body 42 and the roller 21. As described above,
even when the lubricating oil is supplied to the inner peripheral
side of the cage and roller assembly 20, the lubricating oil can
reach the outer peripheral side of the cage 22 by passing through
the cage 22 in the radial direction. The lubricating oil is stored
in the space between the oil reservoir bottom face 43 and the inner
peripheral surface 32 of the planetary gear 10. Then, the stored
lubricating oil is supplied to the guide surface 31 through the
outer recessed groove 51.
[0068] As illustrated in FIG. 3, the oil reservoir bottom face 43
and the bottom 51a of the outer recessed groove 51 are located at
the same position in the radial direction. That is, the oil
reservoir bottom face 43 and the bottom 51a of the outer recessed
groove 51 are located collinearly. Therefore, the lubricating oil
stored in the space between the oil reservoir bottom face 43 and
the inner peripheral surface 32 of the planetary gear 10 easily
flows along the bottom 51a from the oil reservoir bottom face 43,
that is, easily enters the outer recessed groove 51. The outer
recessed groove 51 has the inclined surface 53 as a groove terminal
end face on the axially outer side. The inclined surface 53 has a
shape that extends radially outward with decreasing distance from
the annular portion 23. Therefore, the lubricating oil present in
the outer recessed groove 51 is easily supplied to the guide
surface 31.
[0069] As described above (see FIG. 2 and FIG. 3), the radially
outer surface 52 of the outer claw 40a of the detachment preventing
portion 41 is located on the radially inner side with respect to
the guide surface 31, and the outer recessed groove 51 is recessed
from the radially outer surface 52. With this structure, a part of
the lubricating oil in the outer recessed groove 51 is used for
lubricating the end of the roller 21. That is, on the periphery of
the axial center portion of the roller 21, a relatively large
amount of lubricating oil is present owing to the oil reservoir
bottom face 43. At the axial end of the roller 21, however, the
lubricating oil hardly flows because the detachment preventing
portion 41 is provided. Therefore, the amount of the lubricating
oil may be smaller at the axial end of the roller 21 than at the
axial center portion of the roller 21. According to the structure
described above, the lubricating oil is easily guided to the axial
end of the roller 21 from the outer recessed groove 51 via the
radially outer surface 52 of the outer claw 40a. For example, when
the cage 22 rotates at high speed, a part of the lubricating oil
present in the outer recessed groove 51 may flow out of the outer
recessed groove 51. When the part of the lubricating oil flows out
of the outer recessed groove 51 in the circumferential direction,
the part of the lubricating oil can pass through a space between
the radially outer surface 52 of the outer claw 40a and the inner
peripheral surface 32 of the planetary gear 10 according to the
structure described above. The part of the lubricating oil passing
in this manner is used for lubricating the end of the roller 21.
Thus, the lubricity can be increased also at the end of the roller
21.
[0070] Another advantage can be attained in the structure in which
the radially outer portion 41a provided in the detachment
preventing portion 41 is located on the radially inner side with
respect to the guide surface 31. As described above, the outer claw
40a is elastically deformed in order to house the roller 21 in the
pocket 25 during assembling of the cage and roller assembly 20.
When the outer claw 40a is elastically deformed, a part of the
outer claw 40a may plastically be deformed beyond its elastic
range. As an actual phenomenon, a part of the outer claw 40a may
plastically be deformed so as to be warped radially outward even
when the roller 21 is inserted into the pocket 25 from the radially
outer side while the outer claw 40a is deformed. Even when the part
of the outer claw 40a is plastically deformed, the occurrence of a
case where the outer claw 40a is located on the radially outer side
with respect to the guide surface 31 can be reduced according to
the structure described above. Thus, a part of the cage 22 other
than the guide surface 31 can be prevented from being brought into
contact with the inner peripheral surface 32 of the planetary gear
10.
[0071] As described above, in the second axial guide structure
including the outer recessed grooves 51, the lubricating oil in the
space K (see FIG. 3) is easily supplied to the space between the
guide surface 31 and the inner peripheral surface 32 of the
planetary gear 10. As a result, the sliding resistance between the
guide surface 31 and the inner peripheral surface 32 of the
planetary gear 10 can be reduced, and the heat generation can be
suppressed. Thus, the cage and roller assembly 20 can have high
rotation performance. In this embodiment, the cage and roller
assembly 20 having the structure described above is used in the
support structure 9 that supports the planetary gear 10 (see FIG.
1). Thus, the temperature increase can be suppressed in the cage
and roller assembly 20. Further, the torque of the planetary
gearing mechanism can be reduced because the frictional resistance
is reduced.
[0072] The embodiment disclosed herein is illustrative but is not
limitative in all respects. The scope of rights of the present
invention is not limited to the embodiment described above, but
encompasses all modifications within the scope of structures
described in the claims and their equivalents. In the embodiment
described above, description is given of the case where the cage
and roller assembly 20 is included in the support structure 9 that
supports the planetary gear 10 provided in the planetary gearing
mechanism. The present invention is not limited to this case. The
cage and roller assembly of the present invention is also
applicable to other devices.
[0073] According to the cage and roller assembly of the present
invention, the temperature increase can be suppressed and the
frictional resistance can be reduced by the lubricating oil that
reaches the faces of the annular portions even if the cage is
brought into contact with the mating member located axially
adjacent to the cage.
* * * * *